At $550 - $600 range I would go with AKG C4000B. I went through that same delima a year ago, and have been very happy with my choice.
If you want to save some money, may I suggest the NT-2 for $400. IT will do just as good of a job as the AT4050... if not better.
If you have a little exrta cash and want a real versitle solution I would go to the Sound Room: http://www.oktava.com/ and get an Oktava MC012 ($279) and an M3 Head assembly ($349).
I hear that the KSM32 is very nice, though it has only a cardioid patterern as with the NT2. The 4050 has cardioid, figure 8, and omni. (I really like the ATs, though I hear that the sound of the KSM32 is awesome!!!)
The AKG C4000B has omni, cardioid, and super cardioid. The super cardioid pattern is really handy if you ever decide to use the mic for live applications.
The Oktava mic has the same pattern selections for the small diaphragm. The large diaphragm only has the cardioid pattern.
Actually, the NT2 has cardioid and omni positions and sound great. I used it as the all purpose mic for the "Clyde's Ride" CD. Works great on vocals and horns.